TMC424 Datasheet – (V1.04 / 2015-JUL-01)

11/21

Copyright © 2011 TRINAMIC Motion Control GmbH & Co. KG

4 Dynamic Resolution Adaptation

The dynamic resolution adaptation is needed to link stepper motors and encoders with different

resolutions. The characteristics of the connected hardware must be provided to the TMC424 by sending

the corresponding SPI telegram. (See 5.3.1 Overview on page 13 in this issue). The TMC424 multiplies

the encoder counter by a user selectable value in the range 1..1024, and then divides it by 16. When

using incremental encoders with N channel it is also possible to select between different behaviors

when the N channel is triggered.

Stepper

motor

TMC424

SPI Interface

Stepper Motor:

Resolution: e.g.: 12800 steps / rotation

Encoder:

Resolution: e.g.: 1000 steps / rotation

TMC424:

Prescaler = 3.2 -> 1000* 4 * 3.2 = 12800

Figure 6: TMC424 Application

Table 4 shows a number of prescaler factors for possible combinations of micro step resolution and

encoder resolution. Note: The given number of pulses have to be multiplied by four since 4-times

encoder signal evaluation is used. (See

Channel A

Channel B

Evaluation

Step

Channel N

Figure 10: Encoder Output and Evaluation on page 14).

Microsteps

Encoder Resolution [Pulses / Rotation]

1024

1000

512

500

256

250

200

125

50

25

12800

3.125

3.2

6.25

6.4

12.5

12.8

16

25.6

64

----

6400

1.5625

1.6

3.125

3.2

6.25

6.4

8

12.8

32

64

3200

----

----

1.5625

1.6

3.125

3.2

4

6.4

16

32

1600

----

----

----

----

1.5625

1.6

2

3.2

8

16

800

----

----

----

----

----

----

1

1.6

4

8

400

----

----

----

----

----

----

----

----

2

4

Table 4: Prescaler factors for different motors and encoders